GEOLOGY OF THE MERRIMACK DISTRICT. 539 



given in our Report of Progress for 1872, and in Vol. I, pages 49-51, of 

 this work. The material of this rock is usually a stratified white quartz, 

 varying somewhat in color according to local circumstances. Wherever 

 it bends, and at other parts of its course, it is penetrated by an immense 

 number of veins of a whiter or more milky quartz, insomuch that these 

 veins often constitute the principal part of the rock. The whole bed may 

 have been deposited from thermal waters ; but we do not yet discover evi- 

 dence that the original stratified siliceous material occupied a previously 

 existing fissure. The beds we regard as conforming with the stratification, 

 and as guides in the study of the structure of our rocks. 



The Hooksctt Range of Quartz. Leaving out of view the bed in the 

 south part of Pittsfield, as that may be either Montalban or Rockingham, 

 we find first of all, on the north-east side, ledges of this rock in Aliens- 

 town, in the narrow neck of land between the Suncook river and Hook- 

 sett. Next, in Hooksett, between Lakin's pond and a road turning 

 south-westerly towards the village, are exposures about forty rods long. 

 I think there is another ledge between this and the river. The railroad 

 bridge of the Concord & Portsmouth Railroad, at Hooksett, rests upon 

 ledges of this rock, the two islands consisting of quartz dipping north- 

 west. Next we find it prominently in the Pinnacle, a conical, isolated 

 peak, perhaps three hundred and fifty feet above the river. There is a 

 pretty pond on the west side of it, A little to the south-west, perhaps a 

 mile from the bridge spoken of, is a vein of metalliferous quartz carrying 

 galena. The stratified quartz dips 50° N. W. From the Pinnacle one 

 can look to Hackett's or Whittemore's hill, in the west corner of the 

 town, in a south-west direction, the next conspicuous hill of quartz on 

 this range. The outcrops are numerous between the lead mine and 

 Whittemore's hill, all having essentially the same position, but not so 

 great a width. There is a high hill of it, covered with trees, back of S. 

 Bachelder's. My impression is that the widest part is not over two 

 hundred and fifty feet in breadth. I did not see any outcrop of this 

 quartz along the line of Section HI. It should appear near W. A. 

 Hackett's, near the west town line. The dip of the rocks here is to 

 the north-west, and judging from the position of the strata along the 

 section line, there is a possibility that the quartz may reappear, dipping 

 south-east, in the east part of Bow. South-west from Hackett's the 



